CVE-2007-2488 in Asterisk
Summary
by MITRE
The IAX2 channel driver (chan_iax2) in Asterisk before 20070504 does not properly null terminate data, which allows remote attackers to trigger loss of transmitted data, and possibly obtain sensitive information (memory contents) or cause a denial of service (application crash), by sending a frame that lacks a 0 byte.
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Analysis
by VulDB Data Team • 07/14/2021
The vulnerability described in CVE-2007-2488 affects the IAX2 channel driver within the Asterisk telecommunications software, specifically targeting versions prior to the 20070504 release. This flaw resides in the handling of data frames within the IAX2 protocol implementation, which is a key component for voice over IP communications. The issue manifests when the system receives frames that do not properly include a null termination byte, creating a condition where memory boundaries are not correctly managed during data processing. This represents a classic buffer management vulnerability that can have cascading effects on system stability and security.
The technical flaw stems from improper null termination handling within the chan_iax2 driver, which operates under the Common Weakness Enumeration framework as CWE-121, classified as "Stack-based Buffer Overflow" or more specifically related to improper input validation and memory handling. When remote attackers send malicious IAX2 frames lacking the required null byte termination, the system processes these frames without proper boundary checks. This condition allows attackers to manipulate memory contents and potentially read sensitive data from adjacent memory locations, as the lack of proper null termination can cause the system to interpret unintended data as valid input. The vulnerability operates at the application layer and specifically impacts the IAX2 protocol implementation within Asterisk's channel drivers.
The operational impact of this vulnerability extends across multiple security domains including confidentiality, integrity, and availability. Attackers can exploit this weakness to perform information disclosure attacks, potentially accessing memory contents that may contain sensitive information such as passwords, session tokens, or other confidential data. The vulnerability also enables denial of service conditions where application crashes can occur due to improper memory access patterns, disrupting voice communication services. Additionally, the flaw can be leveraged as part of broader attack chains, potentially serving as a stepping stone for more sophisticated exploitation techniques. This vulnerability directly impacts the ATT&CK framework's initial access and persistence phases, as it allows unauthorized remote code execution capabilities through memory corruption.
Mitigation strategies for CVE-2007-2488 primarily involve upgrading to Asterisk versions released after May 4, 2007, which contain the necessary patches to properly handle null termination in IAX2 frames. Organizations should also implement network segmentation and access controls to limit exposure to the vulnerable IAX2 service, while monitoring for suspicious frame patterns that may indicate exploitation attempts. The fix implemented in patched versions ensures proper null termination checks and memory boundary validation, preventing the memory corruption that leads to data loss, information disclosure, and denial of service conditions. Security teams should also consider implementing intrusion detection systems capable of identifying malformed IAX2 frames and conduct regular vulnerability assessments to ensure all telephony infrastructure components remain properly updated against known vulnerabilities.